<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>D3 Demo</title>
  <script src="https://d3js.org/d3.v6.min.js"></script>
  <style>
    #body {
      margin: 0 auto;
      width: 500px;
      height: 400px;
      background-color: #efefef;
      position: relative;
    }
    .bar {
      width: 30px;
      background-color: green;
      bottom: 10px;
      position: absolute;
    }
    .bar span {
      display: block;
      text-align: center;
    }
  </style>
</head>
<body >
  <div id="body">
   
  </div>
  <script src="app.js"></script>
</body>
</html>